Carbon brush for motors



' (No Model.) 2 sheets-sheet 1.

L. DAFT.

CARBON BRUSH POR MOTORS.

No. 427,674. Patented Mayl, 1890.

(No Model.) 2 Sheets-Sheet 2.

L. DAFT.

CARBON BRUSH ROR MOTORS.

No. 427,674. Patented May 13,1890.

aA/MM( LEO DAET, or

PLAINFIELD, NEW JERSEY, ,TRIO LIGHT COMPANY, OF NEV YORK, N.

ASSIGNOR TO THE DAFT ELEC Y.

CARBON BRUSH FOR MOTORS.

SPECIFICATION forming part of Letters Patent No. 427,674, dated May 13, 1890. Application filed May 23, 1889. Serial No. 311,773. (No model.)

To all whom it may concern..-

Beitknown that I, LEO DAET, of Plainfield, New Jersey, have invented a new and useful Improvement in Combined Carbon Brushes for Electrical Motors and Dynainos, oi' which the following is afull, true, and exact description, reference being had to the accompanying drawings.

My invention relates to an improved contact-maker, or brush, as it is ordinarily called, consisting of carbon combined with a lubricant in various forms, as herein after 1n ere fully specified. A carbon contact-maker or brush is a very beneficial construction Yfor carrying a current to the commutator; but by reason of its lack 0f lubricating quality it possesses an undesirable grinding or wearing action.

By my invention Isecure the benefici. l results of the surface and conductivity of the carbon, together with a lubricating quality not heretofore united in one conductor.

My invention will be readily understood from the accompanyin drawings, in which- Figure l represents a cross-section of my improved brush in its holder; Fig. 2, an elevation of the same; Fig. 3, a cross-section of a modification; Fig. y-i, an elevation of the same. Figs. 5, G, 7, and S represent transverse sections of modifications; and Fig. 9, an elevation of Fig. S; Eig. l0, a cross-section showing the modification, in which plnmbage is mixed with powdered carbon.

l propose generally to malte suitable open- J ings or perforations in a carbon conductor made, for instance, of compressed ground cemented gas-retort carbon or other form of non-lubricating carbon, and insert therein pencils or pins of plumbago having endsprojecting at the wearing-surface. The carbon compound may be of any well-known form, and is shown in the drawings as at A. t Pencils of plumbago are inserted in the carbon,

as indicated. They may be laid in parallel to each other or at an angle to cach other. The surface-contact is generally ground to a circle, as shown, so as to leave a sufficiently large contact-area and permit equal pressure of all its surface, so as to prevent sparking. Instead of inserting the plumbago in pencils, l in ay mix powdered plumbago with powdered carbon, in proportion, say, from [ive to fifty per cent., using coal-tar or molasses to hold the mass together during baking. The obj ect of this combination is to form a conductor of a substance of high conductivity and great lubricating power, so as to reduce the wear of the commutator and increase the smoothness of its operation. There it is desirable to secure a perfectly-noiseless machine for lightruiming purposes, I sometimes find it benefieial to incorporate one to two per cent., by weight, of finely-powdered silicate of magnesia in addition to the plnmbago.

That l claim as my invention, and desire to secure by Letters Patent, is

l. A brush or contact-maker for carrying an electric current to a surface moving thereunder, consisting of non-lubricating carbon and plumbago, substantially as described.

2. An electrical brush or conductor consisting of a non-lubricating carbon body having inserted therein a pencil or pencils of plumbago, substantially as described.

rihe combination of the carbon brush A, having` pencils l B passing therethrough at different angles and projecting at the wearing-surface of the carbon, substantially as described.

ln testimony whereof have signed my So naine to this specification in the presence of two subscribing witnesses.

LEO DAFT.

Witnesses:

ANTHONY GEEF, H. CoUTANT. 

